Recent and anticipated demographic changes in the United States have magnified the concentration of cancer survivors among persons >=65 years of age. At present 60% of the estimated 8.9 million cancer survivors are >=65 years of age and the number of incident cases in this age group is expected to double over the next 30 years. These overall trends are reflected in the specific case of breast cancer. An estimated 203,500 women were diagnosed with breast cancer in 2002, with almost half of the cases occurring in women >=65 years of age. This proportion and the corresponding absolute numbers are likely to grow, because older age is the most important risk factor for breast cancer and because gains in life expectancy will result in more women being at risk for longer periods of time. For these older women, the consequences of breast cancer and its treatment are likely to be complex, due to the interaction of breast cancer treatment sequelae, non-breast cancer comorbidities, and age-related disabilities. We are conducting a multi-site study of over 900 women 65 years of age and older at intermediate and high risk of breast cancer recurrence. We propose to follow this cohort for an average of 10 years following diagnosis to examine the relationships among breast cancer and its treatment, age-related comorbidities and functional impairments, and health outcomes in long-term older breast cancer survivors. Taking advantage of this carefully and comprehensively studied cohort of women whom we have followed since diagnosis, and complemented by Medicare claims data, we will: (1) describe patterns of breast cancer recurrence surveillance and assess the impact of guideline surveillance on breast cancer mortality, all-cause mortality, and health-related quality of life (HRQOL); (2) identify demographic, treatment, and tumor characteristics associated with successful and unsuccessful survivorship with respect to HRQOL, specifically psychosocial and physical function; and (3) determine the impact of a breast cancer diagnosis on total comorbidity burden and quality of non-breast cancer care. Results from the proposed project will provide new information about the large and growing number of older women who are long-term survivors of breast cancer. Understanding their physical, psychological, and medical and oncological care needs will inform the future care of older women with this disease.